1. Field of the Invention
The present invention relates generally to illumination devices and, more particularly, to illumination devices especially adapted to illuminate a keyhole on a door lock.
2. Description of the Prior Art
It is well known that, at night, it is often difficult for a person to see a keyhole in a door lock to insert a key therein. This can pose a safety problem because, in certain localities, it may be unsafe to stand at a locked door and struggle with finding the keyhole. Throughout the years, a number of innovations have been developed relating to illuminating keyholes in door locks, and the following U.S. patents are representative of some of those innovations: U.S. Pat. Nos. 500,026, 2,813,195, 4,533,985, 4,779,171, and 4,872,095. More specifically, U.S. Pat. No. 500,026 discloses an electric lamp for illuminating a keyhole in a door lock wherein the electric lamp is activated by a manually-operated switch. Often a person has one's hands full when one is trying to unlock and open a door. In this respect, one may not readily have a free hand available for manually operating a switch. Therefore, it would be desirable if a keyhole illuminator for a door did not use a manually-operated switch.
Each of U.S. Pat. Nos. 2,813,195 and 4,872,095 discloses a keyhole illuminator for a door lock wherein the source of illumination is located on one side of a door, and the keyhole of the door lock is located at a considerable distance from the source of illumination. Such a distance may be a limiting factor in the amount of light that actually reaches the keyhole and that successfully illuminates the keyhole. In this respect, it would be desirable if a keyhole illuminator for a door had a source of illumination located very close to the keyhole which is being illuminated.
It is noted that a significantly beneficial feature of each of U.S. Pat. Nos. 2,813,195 and 4,872,095 is that each source of illumination is activated by the act of opening of a storm door. Generally, a storm door is not locked and is located outside of the main door of the dwelling which is locked. Generally, one can readily open the storm door without the need of a key and without the need of additional illumination. Thus, it is very desirable for a keyhole illuminator for a door to be automatically activated when the storm door is opened.
Each of U.S. Pat. Nos. 2,813,195, 4,779,171, and 4,872,095 discloses a battery-powered keyhole illuminator for a door lock. Battery-powered illuminators have a number of disadvantages. As the battery power is consumed, the power output gradually decreases, and the amount of illumination provided decreases. In cold weather, batteries provide less power than in warm weather. Worn batteries must be replaced. The battery power source, if exposed to outside weather elements, must be water proof. In this respect, it would be desirable if a keyhole illuminator for a door lock did not depend upon battery power as its power source.
U.S. Pat. No. 4,533,985 discloses a keyhole illuminator that employs an illumination device that swings out from a housing. For purposes of simplicity and convenience, it would be desirable if a keyhole illuminator for a door employs a stationary source of illumination.
Still other features would be desirable in a door lock illumination apparatus. More specifically, the front door areas of dwellings usually have AC-powered porch lights or landing lights. In this respect, it would be desirable if a keyhole illuminator for a door could be powered by the same AC power source that powers the porch lights or landing lights.
Presently, most keyholes for door locks are not provided with a door lock illumination apparatus. In this respect, it would be desirable if a keyhole illuminator for a door could be provided that is readily retrofitted to present door structures.
Thus, while the foregoing body of prior art indicates it to be well known to use door lock illumination devices, the prior art described above does not teach or suggest a door lock illumination apparatus which has the following combination of desirable features: (1) does not use a manually-operated switch; (2) does not depend upon battery power as its power source; (3) has a source of illumination located very close to the keyhole which is being illuminated; (4) is automatically activated when a storm door is opened; (5) employs a stationary source of illumination; (6) is powered by the same AC power source that powers porch lights or landing lights; and (7) can be readily retrofitted to present door structures. The foregoing desired characteristics are provided by the unique door lock illumination apparatus of the present invention as will be made apparent from the following description thereof. Other advantages of the present invention over the prior art also will be rendered evident.